I might be good friends with someone that works at RadioShack or something *cough cough*. (The following does not reflect RadioShack's opinion in any way, etc if the PR people are reading).
RS is undergoing some sort of revamping. From what the memos read, the product selection will change, and I'd expect that its going to see an increase in DIY stuff. The stuff RS is clearancing is stuff that supposedly doesn't sell too well, like a lot of the home theater stuff as mentioned above. From what been observed, that seems pretty accurate. Don't think too many people will miss them. So far the remaining radio equipment has been spared. RS still has rotator cable and guy wire, same price. Recently RS started carrying silver plated PL259s with teflon insulators, which was surprising. They're a little pricey compared to online, but what I would personally consider reasonable for being able to have it "now".
Hint: pricing on radioshack.com can vary from in-store prices, and any item on the website with a Catalog No. starting in 55 is web only, can't be ordered through the store through any special means. Supposedly they can do a radioshack.com order in store, but its essentially the same process as you would do at home, and shipping would still apply.
Any other item not starting in 55 is normally stocked in-store. Depending on the market, product selection may vary. For instance, the RS CB radio (Cat No. 21-164) is a normal item number, but my local store doesn't carry it because of historically low demand for such items in the market. Such items can often be ordered "direct to you" (RS lingo "D2U"). You pay the same price as you would in-store, but they ship the item directly to your home, no shipping charge. Not all items can be D2U'd, I suspect eligibility is determined based on availability and some other factors. Employees can check the eligibility if given the SKU/Catalog No. They can also see if stores nearby have any, or perhaps have some coming in (doesn't update immediately though, so call that store to confirm availability and hold it for you).
As far as RadioShack getting rid of the core product that makes them different from BestBuy, I don't think you'll be seeing that happen anytime soon. Big ticket items like TVs are extremely competitive in price and profit margin. Think about what you can get resistors for at say Mouser in quantities of tens-of-thousands, then think about what you pay for a pack of 5 at RS. Yep, not going anywhere unless the bean counters have gone completely off the deep end (possible). To do that would be the death blow. Its very frustrating to see so much emphasis on cell phones and other low-margin consumer electronics (alienating their traditional consumer base, as many demeaning internet forum posts attest to) when RS could probably do pretty well doing what they've traditionally done best, obviously with some adjustment for the times. Obviously the big-box store model isn't working too well, since most of the big box consumer electronics stores are history. I think there are attempts by management to shift in this direction, but they seem half-hearted. Perhaps the trend is changing though, as we've seen the flood of items set on clearance or otherwise being removed from the store (items that are deemed extremely poor sellers are scrapped, rather than continue to take up space while on clearance).